Hydraulic feed



Nov. 12, 1935. H. J. BREITENBACH 2,020,765.

HYDRAULIC FEED Filed June 2B, 1928 3 Sheets-Sheet l N0V- 12, 1935. H. .1. BREITENBACH 2,020,765

HYDRAULIC FEED Filed June 28, 1928 3 Sheets-Sheet 2 H- J BRExTr-:NBACH HYDRAULIC FEED Nov' 12 5 Sheng-Sheet 3 Filed June 28, 1928 estema Nov. 12, 193s,

UNITED .STATES Application June 28; raza, sei-m N9. 288,902

1s claim. -This invention relates to a hydraulic feeding system for machine tools,and to the application.

of hydraulics for the reciprocation of-a carriage of an engine lathe adapting v5 reclprocated in either forward or reveme directions at normal feedlngrates and atrapid traverse rates by a single piston in direct connection with the carriage.

In the present state of the art, the method nlmost universally employed for the application of hydraulics to machine tool feeding means, where uniformity of movement is required against varying resistance, and at the same time-providing' for variation of the rate of feed movement selectively, yis by variation in volume delivery from the pump or source, 'which may be accomplished in a number of ways. Forinstance, a

"common method is by variation inthe stroke of Athe pump piston. Another' is by employim a plurality of pumps, using them in combination y or singly, etc. All of which require complicated structures and consequent expense; they also occupy considerable valuable space. x

In this device, any commercial means may be employed capable -of delivering liquid in Sullicient volume under required pressure.

An object of lthe invention is to provide a hydraulic feeding mechanism for which will move either the tool into the material lo `or the material against a tool at a uniform feed for a steady and smooth movement, 'regardless cf any variation in feeding pressure, as maybe due to a change in the depth of cut either in an increasing or decreasing. capacity, or other op- :5 erating conditions.

The changes in feeding pressure may occurV rapidly or momentarily as by successive impacts `of the cutter -or eccentrlcity of the cutter or worl. It is therefore necessary that the forward o pressure be variable to meet the eilicient and simple manner. plished by means of a constant volume pump and a valve device, the valve device including a pres,-

5 sure actuated valve, one side of the valve connecting with the cylinder at the power side of the piston, the valve adaptedto be iniluenced by the pressure in the cylinder,V and at an opposite side, a valved and variable by-pass or pump y pressure relief in connection with the pump, and a. deilnite sized or regulatable restriction valve .in the line connecting the pump. and cylinder, the variable by-pass valve establishing a denite and'uniform diner-enna] between the pressures i at the opposite sides of the restriction valve, re-

thecarriagetobe.

machine tools but automatlcaly adjusted various working conditions in an This is accom-f vancement of the the piston sultingin a certain fixed rate of ow to the cyl-v inder a of any variation in feeding pres- The variable by-pass valve is preferably a Weighted valve to cause a constant and uniform l pressure differential between the cylinder land the pump which is quick in operation and thus maintains arelation. between the cylinder pressure and the pump'pressure with no appreciable surging, which may cause detrimental irregularlo ity of tool movement. This automatic/)control is primarily governed vby the pressure in `the cylinder on the power side of the piston, the uid vexhaustr at the oppcsite side of the piston being' through a restricted port during the feeding mo- Il tion lofthe piston, which may be of definite area or through a variable relief valve, as conditions may require. From the variable by-pass or differential valve as it will be hereinafter designated extends two 2o passageways one of which cylinder and the other of is connected to the A which is connected preferably'to a reservoir since this second passag'eway constitutes an escapement for the surplus fluid. In the preferred form adapted to 25" -meet more variable working conditions the passageway .between the differential valve and the cylinder is provided with a feed constrictor which is manually set to provide a predetermined cross section for the passage of the fluid to the cyli`nder. Where more uniform working conditions are anticipated this constriction may be constant or may be simply constituted by the size of Athe connecting pipe chosen. The escape passageway is provided with a constrictor to vary its cross section automatically.

As disclosed, the differential valve consists of a weighted valve member .disposedin a tapered passageway in the escape line. As the source of pressure drives the liquid through the passage- 40 ways to the cylinder, the'weighted valve member in the escape passageway develops a pressure at the source greater than the pressure in the cylinder. If the pressure in the cylinder remains uniform, through uniformity of resistance to adpiston, the valve in the escape passageway willmaintain a constant and uniform opening, allowing a uniform volumetric adapted 35 escape of the liquid to the source of supply, and

a consequent uniform delivery to the cylinder. 5o shouldhowever, resistance to advancement vof vary,'either increasingly or adversely, the valve Vin the escape passage would instantly be activated through a hydrauc lconnection with cylinder to decrease or increase the escape passage proportionately, thereby maintaining a constant and uniform relation between the pressure at the source and that in the cylinder which will cause a uniform volume of liquid to be delivered to the cylinder regardless of varying resistance to advancement of the piston.

The differential in pressure 'is'governed by a constant weight and the variations in pressure between cylinder and pump at the opposite sides of the valve, resulting from any change in feeding pressure causingA increasing or decreasing pump and cylinder pressures, the valve being capable of being alternately influenced by either the cylinder or .pump pressure, with the weight maintaining a denite and constant differential, so that the volume of liquid and rate of iiow to the cylinder will be uniform at either increased or decreased pressures, so that the advancing rate of the piston will be uniform regardless of any opposing pressure applied thereon within the working limits of the tool instituted by a change in depth cut.

This may be further exemplified by the fact that liquid will flow through a given orifice at a uniform rate, provided there is a uniform difference ofphydraulic pressure on each side of the orifice. Assuming that one hundred pounds is on oneside and eighty pounds on the opposite side, liquid will flow through at a certain given rate. If the two pressures are increased, say to two hundred pounds on one side and one hundred and eigh'w pounds on the other side, the same amount of liquid will ov through. the vorifice as in the rst cese, the weighted valve maintaining the constant differential.

Now assumed that it requires twenty-dye pounds hydraulic pressure in the front end of the cylinder to move the piston and its load toward the cut, this pressure is also applied upon the upper side of the plunger in the valve forclng it downward, causing an increased choke to the pump pressure relief and consequent rising pressure.- This movement is opposed by the ilpressure from the pump acting on the lower end of the valve, but theA pressure on the lower end of the valve would be greater than on the upper end by ari-amount equal to the weight,caus ing a higher pressure on one side than on the other, which will give a certain xed rate of flow through the given orice leading to the cylinder, and cause uniform movement of the piston.

'When the tool feeds into the out the hydraulic pressure inthe front end of the cylinder and upper sideof the valve rises, forcing the plunger down, causing an increase in the choke to the relief of the volume from the pump and rise in pressure, giving the same difference as before the'tool fed into the cut but under high pressure toA accommodate for the increase demanded in the feeding pressure. n

The system is easily applicable to a type of machine tool carriage as shown and described in Letters Patent No. 1,600,401, dated September 2l, 1926, in whichv the carriage traverse and tool slide feed is obtained through aV member reciprocable longitudinally of the bed of the lathe,

andv therefore, can be operated by a single piston. The'degree of reciprocation of the piston governs the tool slide movement independent of the carriage, and the carriage and tool slide as a unit for obtaining denite working cycles which can be readily varied through the control of the moving lusten.

annonce The hydraulic system is extremely exible and' easily manipulated either automatically or by the operator and adapting the degree of piston movement to be quickly and accurately controlled for obtaining a definite working cycle of the tool 5 slide or cutting tool, and this ln either direction of the moving piston irrespective of any rate of travel or movement of the piston. lLikewise the feeding rate from a minimum toa maximum can be changed instantly, or the change allowed to take place gradually as may be predetermined bysuitable mechanical or pressure controlling devices for functioning or controlling the operation of the hydraulic system.

The system enables the use of a commercial constant ,volume delivery pump, preferably of a large volume gear type, a control valve for piston direction and rapid traverse control, a differential pressure valve device of preferred design operable automatically for uniform feed regardless of changes in feeding pressure, a back Vpressure relief valve, and the throttle device (either automatically or manually operated) for changing the volume of iiow to vary the rate of piston movement for variable feed.

The application of hydraulic feeding mechanism to the type of machine tool carriage, as referredto in the previously mentioned patent, is easily made without material change in the machine tool organization, by merely substituting a feed rod for the screw feed shaft extending longitudinally of the engine lathe bed, and engaged through the carriage. The feed rod is susceptible to be manually moved for setting, the rod being connected axially to a. piston rod 35 of the hydraulic system. A single power piston only is required for moving the tool slide and its tool upon the carriage and independent of the carriage for either moving the tool toward or from the work and with.v the carriage as a unit for feeding or moving the tool longitudinally of the work.

Other objects and certain advantages will be more fully setV forth in a description of the accompanying drawings forming apart of this 45 specification, in which:

Figure l is a diagrammatic layout of the hy- -draulic feeding and traversing system connected set for feeding the carriage to the right when the main control valve is properly set for feeding carriage movement.

Figures 2 and 3 are diagrammatic views showing the feed control valve set in reverse position from that shown in Figure l, or for feeding the carriage to the left.

Figure 4 isa o1: fu u tic view showing the 60 piston operated by the hydraulic system connectedrto that type of machine tool carriage shown and described in Letters Patent No. 1,600,401, dated September 2l, i926, and illustrating the connection for moving the carriage and cross slide by direct translative movement of vthe piston rod. Figure 5 is a sectional view taken centrally and longitudinally of the dilferential pressure valve, detailing the conmuctionjthereof. 7 Figure 6 is a sectional view taken centrally of thethrottle valve adaptable for use in this system. Y

Figure 'I isa sectional view taken online u '.Flgurefurther detailing tn e construction of the throttle valve.

Figure 8,15 a front elevationof the valve illustrating the graduation marks on the face thereof in combination with the rotatable valve body `for obtaining definite -setting for anyrequired feed.

Referring to the drawings, I indicates a cylinder of the hydraulic system suitably secured to the'machine tool in relation to' the part of the machine to be fed by'the piston 2 within the cylinder connecting with the piston rod lengaging through a stuillng box of the cylinder head I, these elements constituting 'aconverter for the hydraulic force. 'I'he construction of the piston and cylinder may follow any prevailing practice to meet the requirements, with the details thereof beingof no special concern herein.

The opposite ends of the cylinder are in conduit connection with a'control. valve' 5 which,

, as herein illustrated, is of the sliding piston type and from which various conduit connections are made to a reservoir, pump and. dinerential pressure valve. 'Ehe control valve is operated for starting, stopping, and direction reversing, either manually or mechanically through mechanical trip or actuating mechanism, the mechanical operationbeing through a control or trip rod operated by the part of the machine tool moved by the piston or by the piston direct at determined' periods within the maximum movement of the piston, but this phase of the improvement may be variously modined in detail of construction within the concept herein presented and, therefore, is only diagrammatically presented for the purposes of disclosing a complete system as applied to an engine lathe.

The control valve represents a ported cylinder body with a piston valve 6l reciprocable therein for covering or uncovering and connecting vari- 'ous ports for fluid control to and from the cylinder I. The control valve is provided with a trip or. by-'pass valve 'I of poppet type, manually operated by a hand lever 8, and vautomatically by dogs 9- for lstopping the movement for either rapid traverse or feed fat any point in the piston movement and in either direction of movement without affecting the position of the control valve 6.

The trip valve opens communication between port connectingI chambers of -the control valve and a return passage I leading to the reservoir II, so that the pump delivery is by-passed to the reservoir, causing the piston to idle or stop,i the piston travel continuing as soon as the trip valve is closed., .f

Other details of the control valve will be taken up in the description of the various circuits, rapid traverse, and feed.

The rapid traverse circuit is of simple arrangement and controlled entirely by the control valve for direction and trip valve for stopping or starting. Moving the control valve to either of-its limits, right or left, causes an alternate connec tion of the opposite ends of the cylinder to the pump I2 and reservoir I I. The form of rapid traverse circuit as employed is common to hydraulic feeding mechanism for various machine livery, and is utilized for both rapid traverse and feed and, therefore, provides an inexpensiveand very effective unit, with approximately the full .passage I3 and passage I6 within `sage I3, valve chamber I4,.passage 2|, into a the passage I6, through passage 2l, Y upper end of the differential pressure valve con` capacity or regular running-capacity of the pump utilized for rapid traverse.

For the feeding rate the excess volume escapes through the differential pressure valve to the reservointo be-again taken up by the pumpland 5 continuously circulated, the differential valve meanwhile maintaining a uniformly greater pressure at the pump than in the cylinder.

For a rapid traverse in oneV direction and, as illustrated in Figure 1 of the drawings, to the left, the control valve is moved to its extreme right position. VThis placesthe pump in communication with lthe rear -end of the cylinder. The liquid will ilow through a conduit or passage I 3 leading from the pump into the chamber 15 Il of the control valve, thence through the conduit or passage I5 which is connected by the piston valve with the conduit I3 to and into the rear end of the cylinder, thus traversing the piston in a forward direction or' to the left.

The exhaust'from the cylinder at the opposite side ofthe piston is through a passage I6 leading to the control valve. A control chamber` I1 of the valve communicates the conduit I8 in the control valve with the passage I8 connect- Q5 Aing with the reservoir or tank, to be again taken up by the pump for recirculation. Movement of the piston will continue until the piston reaches the end of the stroke, whereupon the high presy sure relief valve I 8 is automatically opened, or 3o ly stopped at any point in its traverse in either direction, and the mechanism is common for rapid, traverse or feed control, which will be more fully hereinafter explained.

Reversing the position of the slide valve from that shown, bringing the same to its extreme forward position, connects the .rear end'of the cylinder with vthe return passages I8 and I0 and the forward end of the cylinder with the passage I3 through the valve chamber I 4 connecting the the control valve.

The feeding circuit for a lathe carriage and its toolslide is controlled by the direction of piston movement and, for moving the piston in a direction to the right, the control valve occupies an intermediate position covering the ports for the passages I6 and I5, and connects the pipe I3 with a passage 2l leading to the lower end 'of a differential pressure valve 22, the entire volume of the pump passing through the paschamber in the.,v diiferential valve wherein the vflow is divided and controlled. A branch leads through a passage 24, including a throttle valve 25, to the forward end of the cylinder, through the passage I6. The relief passage 26 controlled by the differential pressure valve 22 leads back inte the reservoir.

A branch pesage 23 connects with the upper end of the differential pressure valve 22 so that the Y -nects with the forward end of the piston cylinder, and establishes a head pressure on the differential pressure valve corresponding to the pressure within the forward end of the cylinder.

The differential pressure valve comprises (see F'lg.` 5) abody 21 providing a chamber 28 to which the pipe or branch passage 23 is connected for throwing a head pressure upon the 75 and with plunger 29 having aweighted head 3D, the plunger sliding in a bushing 3| secured within the body, the bushing at its lower end having a tapering bore 32 connecting with a passage or chamber 33 `Within the valve body to whicn the conduit or passage 2| is connected, and also Ywith a. passage or chamber 34 in the valve body above the chamber 33 thereof and a port 35 in the bushing, the chamber or passage 31| connecting with the conduit or'passage '25 leading tothe reservoir.

'I'he chamber or passage 33 at the lower end of the plunger also connects with the passage 2c. The plunger with its weighted head is free f tc slide in the bore of the bushing and the lower part of the bushing is bored with a straight hole in advance of the tapered portion. The weighted head ofthe plunger creates a differential pres-- sure between the pumprpressure at the lower end of the plunger and the cylinder pressure within the valve chamber 2B.

The throttle valve 25 interposed in the line of passage 2li regulates the feed orv liquid flow to the cylinder, and through 'its control, variation in the rate oi feed is obtained. The throttle valve in the preferred form herein employed, (see Figs. 6 to 8 inclusive), comprises a valve body having a tapered bore into which a correspondingly tapered plug valve 3B isrotatively engaged. rThe valve is held in place by a collar 3S engaged over the projecting stem 3% of the valve 3E and; hears against the body, and retained by the lock nuts 3?. The body is provided with a pair of radially disposed ports 4B, Il i which are connected or sealed by the valve 38 the valve having a tapered notch 42 out into its periphery for varying the liquid flow between the ports The head of the valve is provided with a square 'stem |53, as shown, for connecting a handle or lever for valve operation, or with a gear for automatic operation as illustrated in Figure 1, or both may be furnished as required. The upper side of the valve body is provided with scale or graduation marks between the limit positions .of the valve to obtain a denite setting or `reading for any desired feed rate.

For lathe utility, an arrangement of elements for feed movement or power traverse of the tool is for both forward and reverse directions, though any combination of direction and rate may be accomplished by suitable structure and setting. In the' capacity for feed of a lathe carriage and its tool slide, it will be assumed that the control valve 6 is shifted to an intermediate p0- sition, closing the port to the passage I and the port of the passagelS, and bringing the valve chamber I4 in a position to communicate from the pump with `the passage 2| connecting with the dilerential pressure valve, whereby communlcation i's established with the passage 2l and through throttle valve 25, with the forward side of the forward end of the cylinder for moving the piston to the right.

- As the load isfincr'eased the pressure proporso as to correspondingly reduce the pump pres,-

aoeoy'es Y l tionately is increasedY and, conversely, as the load is decreased the pressure proportionately is. reduced, the pump, however, operating atA its full volme capacity at all times.

'The throttle valve does not influence the pres- 5 sure but is merely adapted for regulating or varying the feed and provides for readily accelerating or decelerating the rate of feed either in advance of or during the cut, and nits. use cuers greater latitude, although not necessarily required in a Y machine operating at a constant rate in produc- A assembled or grouped with the cylinder to the 20 elimination of piping and reduce the same w a compact hydraulic unit.

For feeding, they volume of liquid is materially less than that required for rapid traverse, and passes through a. restricted passage in order to excite the operation. of the pressure regulator, which causes uniform and even flow of liquid through therestriction and consequent uniform movement of the piston, regardless of the hydraulic pressure required for the feed. The liquid 30 will new through a given orifice at a uniform rate provided there is a. uniform difference -of hydraulic pressure on each side of the orifice.

,The load imposed upon the piston varies withan increase or decrease in cutting depth. An increased' load would tend to retard the piston movement unless there is a corresponding increase in pressure, causing a rise in the pres-v sure in the cylinder at the forward side of the piston, the effect being to force the plunger valve 29 in the differential valve, downwardly, causing an increased choke in the pump relief .passage between passages 33 and 3l controlled by the plunger valve 29, cutting olf and reducing the port area for escape of ,the liquid through the 5 .return passage 3l, resulting in a. rise in the pressure to and lin the line 24 and in the forward end of the cylinder. Pressure exerted in the upper chamber 28 of the differential pressureV valve operates the plunger to force it downwardly. This movement is opposed by the premure from the pump against the lower end of 'the valve,'and the pressure on the lower end of `the valve will be greater than on the upper end by an amount equal to the weight ofthe valve, causing a. higher pressure inVv the lower valve chamber than in theVv cylinder, resulting in a certain fixed-'irate of flow into the cylinder for movement ofthe piston. Y The differential pressure valve acts very quickly'with- 50 out causing any appreciable surging. I

, Conversely, if the pressure in the cylinder lowers by reason o f a, reduction in the load, the pressure on the `lower end of the valve 29 will be greater, and in excess of the differential ilnposed by the weight of the valve and reduced cylinder pressure, resulting in an upward movement ot the plunger, increasing the pump relief sure.

The valve is very sensitive to changes in pressure and quickly establishes the constant differential, so that the feed advancing of the piston will be Aat a uniform rate of the weight of the cut or load imposed upon the piston.v

44 on cylinder head, arresting movement of the piston and causing the hydraulic mesure-delivered by the pump to increase 'opening the high pressure relief valve I9 sothat the liquid from the pump. will escape through the pipe Il and'll connecting with the forward end of the control valve Casing.

This action throws a pressure onthe forward end of the "control valve,' causing the valve to moveto the right until the valve comes in con-v .tact with the rear end of thebody, thereby disconnecting the pump from the forward end of the cylinder and into the rear end of the cylinder, resulting in a reverse of piston movement which may be assumed as a reverse or1 return movement of the carriage to bring the operating machine tool elements back to a starting position. 'I'he return movement will continue until automatically or manually stopped. When slide 6 reaches the rear 'end of the casing, aport I9 is uncovered and connects pipe 2ll with passage I8.

The system provides for pressure regulationV to" adapt it for either forwardor reverse feed, the arrangement as previously described being Y suificient to illustrate a'feed in one direction.-

To feed the piston inthe opposite direction, the" differential pressure valve 22 and throttle .valve 25 are thrown in communication with the rear end of the piston, and therefore for a feed directicnA change, a valve v is included in the system and in the diagrammatic view this valve vis shown in two sections merely for convenience,

`and the by-passes controlled by the Avalve can be arranged in different planes. The valve 45 is interposed in'the passage 20, 20, leading to one 'end' of the` control valve for throwing the line into communication with one end of the cylinder and to the opposite end through a. pipe or A passage 46 connecting with the valve 45.

`, When the valve is thrown in the proper direc- A-ftion, (see Figs. 2 and 3), communication will fhaust fluid and Vtheref 5 the-passage, I6 througha passage 48 and a pas-` be through passage 20, valve 45 andl passage 46 tothe rear or right end of the cylinder and the passage 2U is cut on. AThe valve is likewise inter-posedV within the passage'"24 so as to'dvert the 'fluid' from the diilerential valve into the rear` or right-end of the cylinder, the valve in this instance connecting with .av passage 41 which in turn connects with the is also used to control the back pressure or exoreA has connection with sage 49 connecting with the Vpassage l5 whereby either of said passages 48 and 49 may be alter` nately .thrown into communication with a passage 50 including a back pressure valve 5| and Yconnecting with the return'li'ne or passage I0. nFigurel, the valve '45 is shown in a position for feeding the piston to the right, while the' Figures 2- and v show the reverse position of the valve 45 for feeding the piston to the left. The valve casingV hasgnot been illustrated.

The control valve 6 isprovlded with a rod or -stem 52 extending through 'one end ofthe cylf inder thereof and is preferablyprovidedjwith Anotches for engagement with the spring latch or indes plunger`53 `for locatingfthe piston in its various ,positio'ns'l'he end of the valve rod 52 is connected with a'lever 54 whicl in turn is con- Y Anected to a lrod 55, the Vrod 55 carryinga number of-dogs 9 for actuatingthe-stop-vave 'Il AYThe oppositeend of lthe lactuating rod 5 5 isconncted passage I5. The valve to a hand lever 56. '111e control or actuating rod Il is also connected with a three-arm-lever 51, itsother two arms Carrying rollers 59-59 adapted to be engaged by dogs99-99 mounted 4upon a rod il which is attached tothe carriage and 5 moves in unison therewith. The rod is shown' as broken inthe tic view in order to better illustrate the relation of the various units and their function.

The dogs I9-59 are set to. suitable positions l0 on the rod 6l for tripping or swinging the `threearm lever to either of alternate positions for a,A reverse direction control of the controls'valve. Likewise, the dogs 9-9 are adjustable upon theL actuating rod 55 for stopping the feed or traverse l5 in either direction. Each dog 9 has a plvotednose 9' adapted to abut a cam faced head l on valve l to positivelyhactuate the latter in one'direc- Q tion of movement of rod 5, but to b e tripped .by the head in the opposite direction of movement. 20 In the form shown in the diagrammatic view of `the'fcomplete system, the Lthrottlevalve 25 is illustrated asA provided with a pinion Il connecting to-the stem of the valve and in mesh with a is inmesh with ra'ck teeth of thracks 94-64 relatively disposed at opposite sides o f the rack gear 98 having a tapered upper end for ensagement with the adjustable dogs IVI- mounted upon the trip or control rod 5 9, for 90 providing an automatic operating control of the throttle valve. The upper camf noses of racks 84 are in different vertical planes parallel to rod Il, as are likewise the cam noses of dogs l5. This provides for a-throttle control during the cut- 85 tingfperiod for varying the rate of f In the arrangement shown in Figure 1, with the hydraulic system connected to a commercial type-of lathe, 4the piston rod 3 is connected. to

. the carriage by means of adjust `andyl indicate adjustable nuts or stop collarsf the stop `nuts 4 4 engaging the cylinder head and n the stop nuts $1 engaging a-bracket 68`xed to the bed of the lathe, the stop nuts 44 engaging the cylinder head at the end of a stroke on the 45 forward feedltor in a direction to the right, and

thestop. nuts 61 engaging .the bracket-i8 when (with a pairof air drain valves, 19-'18 connected :s0

together and toa conduit ing with the tank. l

' Considering now the flow of liquid in the hydraulic system, the valve set as shown in Figure Y 1, the liquid will ow from the tank Il by means 55 of the pump l2 deliveredthrough pipe or passage Ilinto the control valve. chamber and throughY pip'e or passage I5'into 'the rear end of the cylin-L der, the'liquid in the front of the cylinder meanwhile escaping or exhausting to the pipe or pase0 ,sage I6. into thecontrol valve chamber" and, out through the exhaustv passages I8 @and I0 back `into -the tank. This causes 'the return power v traverse of the.. piston and carriage connected therewith and 4will continue until the right hand' or passage 1| 'connectdog engages thel roll on the right hand lever w gear-92carryin'garaclrgearllwhichinturnzk Now pushing the handle lever 56 to the right 751.

dog.V 9 upon the rod 55 over the by-pass valve l, allowing the by-pass valve to close, and moves the control piston 6 to its` extreme left position, connecting passages I3 and I 6 intermediate the valve chamber I4, causing the liquid in pipe i6 to flow into a forward for front end of the cylinder for a forward power traverse, the liquid at the rear end of the cylinder meanwhile escaping through passage i5 into the right handvalve chamber il' of the control Vvalve and through a port inthe valve cylinder 5, passages I8 and i0, and back into the tank. l

Moving the hand lever 56 and its rod 55 to the extreme right, raises the left hand arm 58 of the lever 51 to itshighest position and depresses the,

right hand arm 58. Movement of the piston 2 and its connected carriage will continue until the leithand dog 59, previously'set for the commencement o f the feed, comes in contact with the roll of the left hand arm 58, depressing it and moving the rod 55 to the left, and through the lever 54 the piston valve 6 to the right, si-

for the feed passes through passage 24, throttleY valve 2 5, and through the direction valve I5 into the front end of the cylinder. Y

During the feeding motionythe liquid in the rear end of the cylinder escapes through passage l5, passage IS, feed direction control valve l5, back pressure valve 5l, passage 50, haci;V into the tank.` Theback pressure valve may be of any cylinder head I, arresting the feeding motion,

, I9, andthe volume thatpreviously commercial type constituting a spring pressed valve or aweighted type valve, the prsure of Vthe spring regulated by an adjusting screw, permitting the back pressure valve to be adjustedA to cause any desired back pressure on the piston for the purpose of stabilizing thefeed. y Feeding motion will continue until the adjust able nut u on the piston rod 3 contacts with the causing a high pressure inall theV feed -1 s including passage 24 tothe differential pressure valve 22 and the branch passage 23 connecting with the top of the differential pressure valve 2 2 restricting the escape of fluid through the diiferential pressure valve and \.\2l, thereby building up the pressure in the :v Il to a degree'which'will open the pressure relief valve passages 24 and 2B will now pwthrough passage 2li and 2l into the left hand end `of the cylinder of the control valve,` forcing the control valve 6 to its ex'treme right position, the liquid-at the extreme right hand end of the control valve escaping through a small port 13 into the exhaust orreturn passage Il back intothetank.'Any excess pressure at .the left lend of the .valve is relieved throughra port Il' and through a port similar to port 13;

-The moment the piston 6 reach the eil-treme right position, passages I3 and I5 willbeeomected to the intermediate valve chamber. The pressure therefore, immediately drop, relief valve law'ill closeand the whole volume fmmthepump willpassthrough .s e i5 intotherearendof tained to ts. Primarily Vto its extreme position, removes the left hand Ythe cylinder, causing .a return power traverse which will be arrested as previously described.

The feeding direction of the Lpiston just deconveys the carriage in a direction toward the hea'd stock. For conveying or feeding 5 the carriage in a direction away from the head stock, the direction valve I5 must be moved to a reverse position, as shown in Figs. 2 and 3. In this position, passage 2l will be in connection with passage 45, and disconnected from the forward l0 end of the control cylinder, leading and connecting with th'e extreme right hand end ofthe cylinder of the control valve.

Also,`passage 24` connects through valve 45 with the passage 41', connecting with the rear end of l5 the power cylinder. This puts the differential` pressure valve in connection with the rear end of the cylinder and functions substantially the sainev as when connected with Vthe forward'end'of the cylinder.

The direction Vvalve I5, when thus reversed, connects the forward end of the cylinder through passage 48 with the passage 5I, `through back pressure valve 5l, and passage Il, to the tank, so that the forward end of the cylindler is substan- 25 tially the same las previously described for the rear end of cylinder when feeding in the opposite t direction, and the entire operation is likewise the same. t Y

with the nydrauuc system ser for feedingw- 30 and 6I will have to be'appropriatelv adjusted or l one thereof moved out of commission, so that the l entire hydraulic systemis under automatic conf trol. It is not deemed necessary to individually trace allthe circuits and particular functioning of the devices. 45 Afterstarting,the -2- :w willfunction for any appropriate direction of carriage feedto obtain a complete cycle, constituting a, rapid traverseinadirectiomtobringthecutting tool to its cutting position and from thence under automatic control, feeding the carriage and its tool for a distance of feed, thereupon withdrawing the tool and returning the cariage and its-tool hack to its normallposition, reprcsenting one cycle for ordinary turning.

The hydraulic however, is ofadjustienthroughthe settingofthestops anddogaand addingadditional dogstpthenumheroihercyclesand-'controleanheoh-no Vfor one' cycle'after the hand lever has beenappropriately thrown, say :for moving the. piston and carriage inK a forward direction, the. tool moves rapidly towards its cut and will continue f until theappmpriate dog l! actsupon the three-v, arm lever ll for moving theeontrol valve fora liquid feeding new through the differential pres-y Y sure valve.

.At the differential pressure valve the liquid isl divided, the Surplus liquid jbeing back into thetank while the useful or feedingliquid! 1` .passes into the power cylinder. Should the feed- .Ll .ing varyat any time, the differential valvewillfunetionas previously fc-1liV capable 'l increasing or decreasing t a u; the liquid pressure of the pump as thescase may require.

During the 65, depending upon the setto enga-ge a respectiveracke4 for operating feeding action,

either of theY dogs, direction of feed, can be the throttle valve for an increase' or decrease in the rate f feed. After the piston has reached the end of its feeding stroke it will be positively upon the valve will or rapid traverse arrested by the stops on the piston rod, wherebe .controlled to effect a reverse to bring the piston and carriage to rest at their starting position.

'I'he dogs 65 can also control toward the end feeding rate as the 'tool desirable for some tapering form of rate is gradual, instances.

be set for a feeding rate of a cut to change the runs oft, which is highly classes of work, and under the L dogs and racks, the change in which is also of advantage in some To cover a large range of feed, the feed dogs 65 areeither made ferent dimensions, throttle valve regulation adjustable or of relative difas shown, for effecting various Frequently, theamount of metal to be removed Y on various sections of a piece of work varies'considerably. It'is very desirable that automatic change of feed rate be obtained for omaximum production. In some classes of work, it is desirable that when the cutter enters the work the feed rate shall 'be slow. Later, the feed rate may be materially increased,

for a piece reduced.

and thus the cutting timeV Therefore, the dogs can a character to bring throttle regulation tions. 'I'he control be arranged and of such about any determined to meet the existing condi;V of ,the throttle valve is independent of the pressure regulation which is governed by the differentialA pressure valve, and its control only changes the area of the restricted passage and thus varies tween the differential pump on one side and the cylinder on the volume of flow bepressureregulator and the other.

Thus, any desired rate of feed from zero toA maximum can be obtained by merely setting'the throttle valve. This change can be made during the cut if desired,and.the tripping of feed is very accurate and positive.

for a changeA The system, therefore, comprehends any desiredY cycle of feed and quick traverse in either direc-` tion, together withr automatic stop or feed change f at any poi-nt. Thecontrolled devices being posi` tive in their action, are change in loads/requiring a decrease in pressure, except that which is automatically accommodated by the di The feeding and rapid traverse circuits can benut in, and out at any point and theV feed rate not inlue ed by any r increase il'erential pressure valve.V

varied, and automatically cntroliedto adjust the feed rate tothe amount desired cessiv/e carriage positio tremely flexible and economical in operation, and

foreach sucn'. 'I'he system is exthe devices employedsofvery simple design, sturdy l in construction,

The feeding rate at and .of longlife.V 1 which the piston moves for aglven throttle setting does not change with the change in resistance to the movement of the piston.- Greater or lesser resistance-to the ipovement of the piston raises with the differential valve or lowers'the pressure, maintaining a constant differential to insure unifornityrin feed.

' The differential press ure valve thus' converts feed being delivered to v slide and from the work,

t -7 the pumping unit from what might normally be termed a rapid traversecapacity, into a variable feeding capacity by imposing a choke, thus di-V viding the volume, the required volume for the the cylinder andthe sur,- plus passing back into the tank.

, As the resistance is decreased,there is a-correspondingly less`impedance in the return of the surplus to thetank, thus, a lower back pressure, so that there is no strain on the pump other than that required for the feed.4

'Ihe pump is always ready to deliver at its maximum feeding force, and can continue so for long pcriodsvwithout strain `or perceptible wear, requires no adjustment l ing conditions, and enables the use of the simplest type of` pump.

In Figure 4, the piston of thehydraulic 'system to meet the various workl5 is shown as connecting with a feed rod of alathe carriage of Vthe type The feed rod reciprocating'with the pisf, ton is connected to a 'sleeve having a rack on one side for transmission connection with the tool slide, substantially-as disclosed in said patent.

The sleeve ments on the carriage, the abutments spaced to provide an intermediate non-carriage feedingv O traverse of the sleeve rack` for independent toolfeed. When the rack abuttingly .engages the carriage in either direction of piston 'move- 30.. ment the carriage and slide move as a unit and in either direction of piston movement.

'Ihe structure illustrated permits the sleeve rack to be adjusted upon the feed rod for carriage Y Y adjustment upon the'lathe-bed by manually ro- 35 tating the feed rod. For further description of th4 parts of this lathe organization reference is lmade to said patent, the disclosure herein being sumcient for the present purpose to feature a feed for theA carriage and'y tool rocation of a feed rod actuated by a piston; the piston under control for feed and traverse rates of motion.

'asshown in said aforesaid 20 is'dlsposed between opposing abutslide through the recip- 40 lol The tool slide is thas capable ,of being :ed to.

and' subsequent feed with dinally of the work. l Y

Having described my invention, I claim; 1. A valve device for hydraulic feed system,

' the carriage longitu'- thevalve dividing and controlling apump de- 50 livery, comprising a valve body formed with com-I municating inlet -and restricted outlet and a valve controlled second outlet, theinlet connecting with `a pump supply, the restricted outlet with a cyl- .inder, arid the valve,controlled second outlet as a regulatable escape, anda valve for said second outlet exposed to relatively opposing cylinder and pump pressures, with the prevailing pressure moving said valve for operative control, and the .valve normally 'imposing a' determined resistance upon the pump volume to establish a constant differential between pump andcylinder pressures. 2. In a lathe, a carriage, a tool slide thereon.'

a reciprocating feed rod, a'member on said feed rod moving therewith and in transmission .con-

nection with said tool slide and having adetermined non-carriage, engaging motion for tool slide feed and `engageable with the carriage for while the carriage is` at rest,v

carriage feed with the slide as a unit, aridhydraulicl means including a reciprocating said feed rod, controllable for move piston and cylinder for ing the piston at feeding and rapid traverse rates.

3. In a machine of the class described, a recip- 'rocable member,

a cylinder and piston, one .of

whiclris connected with said member, fluid pressure generating means, a fast feed conduit and a slow feed conduit connecting the generator with an end of the cylinder, and a valve operated by the member in it`s advance under fast feed to cut in the slow feed conduit at a predetermined point. f A4. In a machine of the class described, a

reciprocable member subject to variable resistance to its movement, a cylinder and piston, one of whichl is connected with said member to move it, a source of fluid under pressure, conduits Vadapted to connect the source with either end upon said movable element to vary the escape through said orifice.

5. In a machine of the class described, a reciprocable member subject to variable resistance to its movement, a cylinder and piston, one of which is connected with said member to move it, a. source of fluid under pressure, conduits adapted to connect the source'with eithere'nd of the cylinder, valve means controllable to connect the source alternately with said conduits to reciprocate the piston, an escape valve between the source and cylinder to control the pressure supply to the, latter, said escape valve including a movable element and having an escape orlce controlled by said element, a connection for imposing the varying pressure withinthe cylinder upon` saidmovable lelement to vary the escape through said orifice, and mechanical means yielding ly. urging said` movableelementl in closing relation to said orifice. l

6. Ina machine of the class described, a reciprocable member subject to variable resistance to itsmovement, a cylinder and piston, one of which is .connected .with saidmember .tol move it, a source of iiuid under pressure, conduits adapted to connect the source with either end of the cylin-` der,'va l ve means controllable to connect the v source alternately with said conduits to rciprof cate thepiston, an escape valve between the source and-cylinder to control the pressure supply to theY latter, said escape valve including a movable element and having an escape orifice .controlled by Vsaid element, a connection for imposing the'varying pressurewithin the cylinder upon said movable element to 'vary the escape through saidi orifice, and controllable flow restricting means interposedbetween saidescape -valve and cylinder.

. 7. In ia machine-of the class described, a r

A ,ciprocable member subject to variable resistance to its movement, a cylinderand pistonyone o f which connected with'said memberto move it, a source of fiuid under pressure, conduits adapted to connect the source lwith either end of the cylinder, valve means controllable to connect the source alternately with said conduits to'revcipro'cate the piston, zin-escape valve between the source and cylinder to control theI pressure supply to the latter, said escape' valve including a movable .element and having anescape orice controlled by said element, a connection f or iml posing the varying pressure* within the -cylinder upon said movable 'element to vary the escape through said orifice, mechanical means yieldingly urging said movable element in closing relation to said oriiice,fand controllable iiow restricting means interposed between said escape valve and cylinder. 8. In a machine of the class described, a reciprocable member, a cylinder and piston, one of which is secured to said member, a source of iiuid under pressure, a'valve, a supply conduit connecting said source and valve, a fast feed 10 conduit and a slowfeed conduit connecting said valve and cylinder, said valve operable to connect the supply conduit with either the fast or slow feed conduit, and means controlled by movement of said member to move the valve to throw 15 the supply from the fast to the slow feed conduit.

9. In a machine of the class described, a reciprocable member, a cylinder and piston, one of which is secured to said member, a source of fluid under pressure, a valve, a supply conduit con- 20 necting said source and valve, a fast feed conduit and a slow feed conduit connecting said valve and cylinder, said valve operable to connect the supply conduit with either the fast or slow feed conduit, an escape valve in the slow 25 feed conduit, and means for controlling saidf escape valve in dependence upon the uid pressure existing in the cylinder.

van escape valve in the 4slow feed conduit, land@ means for controlling said escape valve in dependence upon the fluid pressureexisting in the cylinder.

11. In a machine of the class described, a reciprocable member, a cylinder and piston, one of 45 which is secured to said member, a ,source of` fluid under pressure, a valve, a supply conduit connecting said .source and valve, a fast feed conduit and a slow feed conduit connecting said valve and cylinder at one end' of the latter, and 50 a fast feed conduit connecting Ythe valve and `cylinder at the other end of the latter, said valve being operative to connect thev supply conduit with either of the fast yfeed conduitsor the slow 56 feed conduit. Y

-12. I n 'a machine of the class describeda. reciprocable member, a cylinder and piston; one of which is securedto said member, a source` of fluid under 'pressurea valve, asupply conduit connecting said source and valve, a fast feed con w duit and a slow feed conduit connecting said valve and cylinder at one end of the latter, a fast fed "conduit connecting the valve and oylinderat the other end of the latter, said valve being .opera-,5 tive toconnect the supply'conduit with either of the forst feed Vconduits'or the slow feed conduit,

and means controlled by movement of said niember `in-one direction Vto move 'the valve to throw Athe supply from the nist mentioned fast feed con- @uit t0 the 810W feed conduit.'l

13. In amachine of thel class described, a' reciprocablemember, a cylinder and piston, one :of which is to said member, a source of fluid under pressure, a valve, a supply, conduit connect- To* mg said somiand valve, a mi feed conduit ma a slow feed conduit connecting said valve and cylinder at one end of the latter, a fast feed conduit connecting the valve. and cylinder at the other end of the latter, said valve being operative toconnect the supply conduit with either of the fast feed conduits or the slow feed conduit, means controlled by movement of said member in one direction to move the valve to throw the supply from the first mentioned fast feed conduit to the slow feed conduit, and means automatically actuated at the limit of movement of said member in one direction to move the valve to throw the supply to the second mentioned fast feed con- 15 duit.

14. In a machine of the class described. a reeiprocable member, a cylinder and piston, one of which is secured to said member, a source of iiuid under pressure, a valve, a supply conduit connecting said source and valve, a fast feed conduit and a slow feed conduit connecting said valve and cylinder at one end of the latter, a fast feed conduit connecting the valve and cylinder at ,the

' other'endof the latter, said valve being operative to connect the supply conduit with either of the fast feed conduits or the slow feed conduit, and a valve operable to reverse the relation of said feed conduits to the cylinder ends.

15. In a. machine of the class described, a reciprocable member, a cylinder and piston, one of which is connected with said member, a source of fluid under pressure, conduits connecting said source with the cylinder ends, a valve operable inder and the other for discharge therefrom, means actuated upon movement of said member in one directionto move said control valve to connect the iluid supply for movement of the member in the opposite direction, and an exhaust valve for the uid pressure medium automatically 16. In a machine of the class described, a reciprocable member, a cylinder and piston, one of which is connected with said member, a source of iiuid under pressure, conduits connecting said to control one of the conduits for feed to the cyllopened upon such movement of the control valve.'

inonedirectioutoxnoveaaidcontrolvaiveto connect the uuid Simply' for movement of the Amember in the opposite direction, a dog movable with said member, a spring-cloud exhaust valve for the uid pressure medium, and means on said exhaust valve engaged by the dog to open the exhaust valve as the control valve is moved as above specified 17. Ina machine ofthe described. a reciprocable member. a cylinder and piston, one of lo which is connected with said member, a source of fluid under pressure, a valve comprising an element movable to control pressure uid supply to sailLcylinder for either fast or slow feed or fast rettnn, fast and slow feed conduits connecting -18 said valve and one end of the cylinder and a-return conduit connecting said valve and the other end of the cylinder, said valve having limit positions wherein it connects the sourceto the return conduit or -to the fastfeed conduit, respectively, ll)v and an intermediate position wherein it connects the source to the slow feed conduit, means for moving said valve to intermediate position at the end of the return movement of said member, and an exhaust valve forthe fluid pressure medium 2li automatically opened when the control valve'is so moved. a

y 18. In a machine of the class described, a reciprocable member, a cylinder and piston, one of which is connected with said member, a source of l0 fluid under pressure, a valve comprising an ele-` ment movable to control pressure fluid supply to said cylinder for either fast or slow feed or fast return, fast and slow feed conduits connecting said valve and one endvof the cylinder and a return conduit connecting said valve and the other end of the cylinder, said valve' having limit positions wherein it connects the source to the return conduitA or to the fast feed conduit, respectively, and an intermediate position. wherein it 40 A connects the source to the slow feed conduit, means for moving said valve to intermediate position at the end of the return movement of 'said member, and an exhaust valve for the fluid pressure medium automatically opened when .the conl5 4trol valve is so moved, said control valve being movable from fast feed position to slowfeedposition without opening said exhaust valve. Y 

